CN113167073A

CN113167073A - Multi-head additive printing device for manufacturing wind turbine tower structure

Info

Publication number: CN113167073A
Application number: CN201980078899.XA
Authority: CN
Inventors: N·A·特恩奎斯特; J·R·托宾; K·拉马杜赖; K·P·阿南丹
Original assignee: General Electric Co
Current assignee: General Electric Renovables Espana SL
Priority date: 2018-09-28
Filing date: 2019-09-24
Publication date: 2021-07-23
Also published as: US11970875B2; WO2020068793A1; EP3857003A1; US20220049521A1

Abstract

A system for manufacturing a tower structure of a wind turbine includes an additive printing apparatus having a central frame structure with a platform and an arm member. The arm members are substantially parallel to the longitudinal axis of the tower construction. The additive printing apparatus further comprises a plurality of robotic arms secured to the arm components of the central frame structure. Each of the robotic arms includes a printer head for additive printing one or more materials. The additive printing device also includes at least one nozzle configured to dispense the bonding material. Further, the system includes one or more dies that are additively printed via an additive printing device of the polymeric material. Thus, the mould defines an inner wall limit and an outer wall limit of the tower structure. After the mold is printed and cured, at least one of a nozzle or a printer head of the additive printing device is configured to distribute the bonding material between the inner and outer wall limits of the tower structure.

Description

Multi-head additive printing device for manufacturing wind turbine tower structure

Technical Field

The present disclosure relates generally to wind turbine towers, and more particularly to a system and method for manufacturing wind turbine tower structures using a multi-head printer that allows tower reinforcements to be printed simultaneously along with concrete to create a complete assembly on site.

Background

Wind power is considered one of the cleanest, most environmentally friendly energy sources presently available, and wind turbines have gained increased attention in this regard. Modern wind turbines typically include a tower, generator, gearbox, nacelle, and one or more rotor blades. The rotor blades capture kinetic energy of wind using known airfoil principles. The rotor blades transmit kinetic energy in the form of rotational energy so as to turn a shaft that couples the rotor blades to a gearbox (or directly to the generator if a gearbox is not used). The generator then converts the mechanical energy to electrical energy, which may be deployed to a utility grid.

Wind turbine towers are generally constructed from steel tubes, precast concrete sections, or a combination thereof. Furthermore, the pipes and/or concrete sections are typically not formed on site, shipped on site, and then arranged together to erect the tower. For example, one method of manufacture includes forming precast concrete rings, shipping the rings to the site, placing the rings on top of each other, and then securing the rings together. However, as wind turbines continue to grow in size, conventional manufacturing methods are limited by transportation regulations that prohibit the shipment of tower sections having diameters greater than about 4 to 5 meters. Thus, certain tower manufacturing methods include forming a plurality of arc segments, and securing the segments together in the field to form the diameter of the tower, such as via bolting. However, such methods require a significant amount of labor and can be time consuming.

In view of the foregoing, the art is continually seeking improved methods for manufacturing wind turbine towers. Accordingly, the present disclosure is directed to a method for manufacturing a wind turbine tower structure that addresses the above-mentioned problems. In particular, the present disclosure relates to methods for manufacturing wind turbine tower structures that utilize simultaneous printing of tower reinforcements along with concrete to produce a complete assembly on site.

Disclosure of Invention

Aspects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.

In one aspect, the present disclosure is directed to a method for manufacturing a tower structure for a wind turbine. The method includes printing, via a first printer head of an additive printing device, at least a portion of one or more molds of a tower structure of a wind turbine of polymeric material on a base of the tower structure. The mold defines an inner wall limit and an outer wall limit of the tower structure. After the portions of the mold are cured, the method includes providing a bonding material between the inner and outer wall limits of the tower structure via a second printer head of the additive printing device while continuously building one or more additional portions of the mold with the polymeric material. While the additional portions of the mold continue to cure, the method includes continuing to fill one or more additional portions of the mold with the bonding material until the tower structure is established. Further, the method includes allowing the bonding material to cure within the mold to form the tower structure.

In one embodiment, providing the bonding material between the inner wall limit and the outer wall limit via the additive printing device may comprise additive printing the bonding material between the inner wall limit and the outer wall limit via the additive printing device. In an alternative embodiment, providing the bonding material between the inner wall limit and the outer wall limit via the additive printing device may comprise dispensing the bonding material between the inner wall limit and the outer wall limit via at least one nozzle of the additive printing device.

In another embodiment, the additive printing device may comprise a plurality of robotic arms, wherein each of the robotic arms has a printer head for dispensing the polymeric material and the bonding material, respectively. In further embodiments, the method may comprise mounting a central frame structure of the additive printing device between the molds. Further, the center frame structure has a platform and arm members extending generally perpendicularly therefrom. Furthermore, the robot arm is fixed to an arm part, wherein the arm part is substantially parallel to the central longitudinal axis of the tower construction. In such embodiments, the nozzle of the additive printing apparatus may be mounted to the arm member, and optionally may be configured to move along a longitudinal axis of the arm member.

In additional embodiments, the method may further include translating the platform in a vertical direction to move the central frame structure and the plurality of robotic arms along the central longitudinal axis of the tower structure during printing of the bonding material. More particularly, in one embodiment, translating the platform in the vertical direction may include providing a movement mechanism configured to move the central frame structure within the tower structure and allow for a change in diameter of the tower structure as the additive printing device is moved along the central longitudinal axis to print the plurality of tower sections.

In several embodiments, the method may further comprise rotating one or more of the plurality of robotic arms about the central frame structure. In a particular embodiment, the height of the additive printing device may be determined such that once a first section of the tower structure is printed, the additive printing device may be moved to a second vertical position to print a second section of the tower structure.

In further embodiments, the method may include printing one or more guide structures for a plurality of robotic arms into the bonding material and/or the polymeric material via the additive printing device. In further embodiments, the method may further comprise dispensing additive into the bonding material and/or the polymeric material via an additive printing device to form one or more reinforcing elements. The additive may include, for example, a metallic material, a composite material, a non-metallic material, or a combination thereof. In another embodiment, the method may include providing an adhesive material between at least one of: a bonding material to the base, a bonding material to the polymeric material, a bonding material to the metallic material, or multiple layers of bonding material, polymeric material and/or metallic material. In several embodiments, the method may further include manually placing the one or more reinforcing elements in at least one of the bonding material or the polymeric material before, during, or after printing and before curing.

In such embodiments, the reinforcing elements may include, for example, sensors, elongated cables or wires, helical cables or wires, reinforcing bars (hollow or solid), reinforcing fibers (metal or polymer), reinforcing metal rings (circular, oval, helical, and others as may be relevant) or couplings, meshes, and/or any such structure as may be known in the art to reinforce concrete structures.

In another aspect, the present disclosure is directed to a method for making a bonded structure. The method also includes printing, via a first printer head of the additive printing device, at least a portion of one or more molds of the structure of polymeric material on the base of the structure. The mold defines an inner wall limit and an outer wall limit of the structure. After the portions of the one or more molds have cured, the method includes providing, via a second printer head of the additive printing device, a bonding material between the inner and outer wall limits of the structure while continuously establishing additional portions of the one or more molds with the polymeric material. While the additional portions of the mold continue to cure, the method includes continuing to fill the additional portions of the mold with the bonding material until the structure is established. Further, the method includes allowing the bonding material to cure within the one or more molds to form the structure.

In yet another aspect, the present disclosure is directed to a system for manufacturing a tower structure for a wind turbine. The system includes an additive printing device, such as a 3D printer. An additive printing apparatus includes a central frame structure having a platform and arm members extending substantially perpendicularly therefrom. The arm members are substantially parallel to the central longitudinal axis of the tower construction. Further, the additive printing apparatus comprises a plurality of robotic arms fixed to the arm members of the central frame structure. Each of the robotic arms includes a printer head for additive printing one or more materials. The material may include, for example, a polymeric material, a bonding material, and/or a metallic material. Further, the additive printing device comprises at least one nozzle configured for dispensing the bonding material. Further, the system includes one or more dies that are additively printed via an additive printing device of the polymeric material. Thus, the mould defines an inner wall limit and an outer wall limit of the tower structure. Thus, at least one of a nozzle or a printer head of the additive printing device is configured to distribute the bonding material between the inner and outer wall limits of the tower structure.

It should be understood that the system may also include any of the additional features as described herein. For example, the system may further include one or more reinforcing elements for reinforcing the bonding material. In another embodiment, the polymeric material may comprise a biodegradable polymer configured to degrade/disintegrate over time. In additional embodiments, the system may include a separate fluid delivery system for each of the one or more materials.

These and other features, aspects, and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention.

Drawings

A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures, in which:

FIG. 1 illustrates a perspective view of an embodiment of a wind turbine according to the present disclosure;

FIG. 2 illustrates a partial cross-sectional view of one embodiment of a tower structure for a wind turbine manufactured with an additive printing device according to the present disclosure;

fig. 3 shows a schematic diagram of one embodiment of an additive printing device according to the present disclosure;

4A-4D illustrate perspective views of various embodiments of a print nozzle of an additive printing device according to the present disclosure;

FIG. 5 illustrates a top view of an embodiment of a tower structure for a wind turbine made in accordance with the present disclosure;

FIG. 6 illustrates a partial side view of an embodiment of a portion of a tower structure for a wind turbine made in accordance with the present disclosure;

FIG. 7 illustrates a partial side view of an embodiment of a portion of a tower structure for a wind turbine made in accordance with the present disclosure;

FIG. 8 illustrates a flow diagram of an embodiment of a method for manufacturing a tower structure for a wind turbine according to the present disclosure; and

fig. 9 illustrates a block diagram of one embodiment of a controller of an additive printing device according to the present disclosure.

Detailed Description

Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For example, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. It is therefore intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

In general, the present disclosure relates to methods for manufacturing wind turbine towers using automated deposition of bonding materials via techniques such as additive manufacturing, 3-D printing, jet deposition, extruded additive manufacturing, concrete printing, automated fiber deposition, and other techniques that utilize computer numerical control and multiple degrees of freedom to deposit materials. More particularly, the method of the present disclosure includes simultaneous printing or inclusion of tower reinforcement elements along with concrete to produce a complete assembly on site. In one embodiment, for example, a method of the present disclosure includes using polymer additive manufacturing techniques to establish inner and outer wall limits of a tower segment with a gap in between for concrete. Such methods are implemented with multi-head printers, where one printer head dispenses concrete and another printer head prints the polymer material.

More particularly, the multi-head printer may include robotic arms each having a printer head mounted at a distal end thereof, wherein the printer heads are mounted on a central frame structure. Thus, the robot arm can move and swivel along the central frame structure. Structural reinforcement may also be added to the concrete during the printing process. Furthermore, the length of the central frame structure may be as short as required so that once a certain height of the 3D printed concrete tower is set, the robotic arm may be converted to move along the concrete tower. One or more guide structures for the robotic arm may also be 3D printed in a polymer mold that is subsequently filled with concrete. Thus, when the concrete sets, the polymer mold may be formed of a biodegradable polymer configured to degrade/decompose over time so as to expose the guide structure. In additional embodiments, at least a portion of the polymer mold may be melted to expose a concrete guide structure that may support a printer for building a tower therefrom. Additionally, the robotic arm may be mounted on the movable platform with at least one linkage to allow the tower to contract in diameter when the arrangement is moved upwardly. In another embodiment, one or more of the polymer printer heads may also be supplemented and/or replaced with a metal printer head to print metal reinforcements into concrete. Alternatively, the rebar may be placed into the concrete, i.e., without the need for a separate printer head.

Thus, the methods described herein provide many advantages not present in the prior art. For example, because the polymer printing process is able to cure into the structure faster than concrete, the molds described herein may be printed to allow a greater amount of concrete to be injected into the mold along with the metal reinforcement. Thus, the method of the present disclosure increases manufacturing speed and provides structural advantages over concrete alone. The mold also provides environmental protection to the cured concrete. In other words, the mold provides environmental protection to the cured concrete when the printing process is done externally without the need for additional structure to be erected in the field. Thus, the mold is configured to reduce and/or eliminate exposure to rain, snow, sleet, and the like. Polymer-printed molds also enable a larger draft angle for tubular structures relative to concrete-only printing.

Referring now to the drawings, FIG. 1 illustrates one embodiment of a wind turbine 10 according to the present disclosure. As shown, the wind turbine 10 includes a tower 12 extending from a base 15 or support surface, with a nacelle 14 mounted atop the tower 12. A plurality of rotor blades 16 are mounted to a rotor hub 18, and rotor hub 18 is in turn connected to a main flange, which rotates a main rotor shaft. The wind turbine power generation and control components are housed within the nacelle 14. The diagram of fig. 1 is provided for illustrative purposes only to place the present invention in an exemplary field of use. It should be appreciated that the present invention is not limited to any particular type of wind turbine configuration. In addition, the present invention is not limited to use with wind turbine towers, but may be used in any application having concrete construction and/or tall towers in addition to wind towers (including, for example, dwellings, bridges, tall towers, and other aspects of the concrete industry). Furthermore, the methods described herein may also be applied to the fabrication of any similar structure that would benefit from the advantages described herein.

Referring now to FIG. 2, a partial cross-sectional view of one embodiment of tower structure 12 of wind turbine 10 is shown according to the present disclosure. As shown, tower structure 12 may be formed from a plurality of

sections

25, 27. More specifically, as shown, tower structure 12 has a first tower section 25 and a second tower section 27. In addition, the illustrated tower 12 defines a circumferential tower wall 20 having an outer surface 22 and an inner surface 24. Further, as shown, the circumferential tower wall 20 generally defines a hollow interior 26, which hollow interior 26 is generally utilized to house various turbine components (e.g., power converters, transformers, etc.) along different locations in the tower 12. Additionally, as will be described in greater detail below, tower structure 12 is formed, at least in part, using additive manufacturing. Further, as shown, the tower structure 12 is formed from a bonding material 28, which bonding material 28 may be reinforced with one or more reinforcing elements 30. In particular embodiments, the reinforcing elements 30 described herein may include, for example, sensors, elongated cables or wires, helical cables or wires, reinforcing ribs (hollow or solid), reinforcing fibers (metal or polymer), reinforcing metal rings (circular, oval, helical, and others as may be relevant) or couplings, meshes, and/or any such structure as may be known in the art to reinforce concrete structures. As such, the reinforced tower structure 12 is configured to withstand wind loads that may cause the tower 12 to be susceptible to cracking.

Additionally, as used herein, the bonding material 28 may include any suitable applicable paste configured to bond together to form a structure after curing. Suitable cementitious materials include, for example, hydraulically setting materials based on lime or calcium silicate, such as portland binders, fly ash, blast furnace slag, pozzolans, limestone fines, gypsum or silica fume and combinations of these. In some embodiments, the bond material 28 may additionally or alternatively include a non-hydraulically setting material, such as hydrated lime and/or other materials that harden by carbonization. The cementitious material may be combined with fine aggregate (e.g., sand) to form a mortar, or with coarse aggregate (sand and gravel) to form concrete. The cementitious material may be provided in the form of a slurry that may be formed by combining any one or more cementitious materials with water and other known additives including accelerators, retarders, extenders, weighting agents, dispersants, fluid loss control agents, lost circulation agents, strength decay prevention agents, free water/free fluid control agents, bulking agents, plasticizers (e.g., superplasticizers such as polycarboxylate superplasticizers or polynaphthalene sulfonate superplasticizers), and the like. The relative amounts of the respective materials provided in the bonding material may be varied in any manner to achieve the desired effect.

3-8, the present disclosure relates to a method for manufacturing a wind turbine tower via additive manufacturing. As used herein, additive manufacturing is generally understood to encompass processes for synthesizing three-dimensional objects, wherein successive layers of material are formed under computer control to produce the object. Thus, objects of almost any size and/or shape can be generated from the digital model data. It should also be understood that the additive manufacturing method of the present disclosure may include three degrees of freedom as well as more than three degrees of freedom, such that the printing technique is not limited to printing stacked two-dimensional layers, but is also capable of printing curved shapes.

Referring specifically to FIG. 3, a schematic view of an embodiment of a system 32 for fabricating tower structure 12 of wind turbine 10 is shown. As shown, the system 32 includes an additive printing device 34, such as a 3D printer. It should be understood that additive printing device 34 described herein generally refers to any suitable additive printing device having one or more printer heads and/or nozzles for depositing material (such as polymeric material 36 and/or bonding material 28) onto a surface, which is automatically controlled by controller 76 to form a computer-programmed object (such as a CAD file).

More particularly, as shown, additive printing apparatus 34 includes a central frame structure 38, with central frame structure 38 having a platform 40 and arm members 42 extending substantially perpendicularly therefrom. Further, as shown, arm members 42 extend substantially parallel to a central longitudinal axis 44 of tower structure 12. In addition, as shown, additive printing apparatus 34 includes a plurality of robotic arms 46 that are secured to arm members 42 of central frame structure 38. Further, as shown, each of the robotic arms 46 includes a printer head 48, 49 each having a print nozzle 51, 53 for additive printing one or more materials.

The material may include, for example, a polymer material 36, a bonding material 28, a metal material 50, and/or an adhesive material 33. In addition, as shown, the robotic arm 46 is mounted to rotate or swivel about the arm member 42 of the central frame structure 38 during printing of various materials. For example, in such embodiments, the robotic arm 46 may be mounted to a rotational bearing that is mounted to the central frame structure 38.

Additionally, fig. 4A-4D illustrate perspective views of various embodiments of print nozzles 51, 53 of additive printing device 34 according to the present disclosure. More particularly, as shown, fig. 4A shows one of the print nozzles 51, 53 having a plurality of integrated adhesive ejectors 55 for applying adhesive material 33 to the bonding material 28 that has been or is being printed. Fig. 4B shows one of the print nozzles 51, 53 with a separate binder sprayer 55 for applying the binder material 33. In such embodiments, a separate adhesive ejector 55 may or may not contact the print nozzles 51, 53. Fig. 4C shows a cross-sectional view of one of the print nozzles 51, 53 having a plurality of integrated adhesive ejectors 55, the adhesive ejectors 55 being configured to apply the adhesive material 33 to the periphery of the bonding material 28 as it is extruded from the print nozzles 51, 53. Fig. 4D shows one of the print nozzles 51, 53 with a plurality of integrated adhesive ejectors 55, which adhesive ejectors 55 are configured to eject adhesive material 33 on the bonding material 28 just after it exits the print nozzles 51, 53.

Further, the additive printing device 34 may include at least one injector 52 configured to dispense the bonding material 28. Further, system 32 includes one or more dies 54 that are additive printed via additive printing device 34 of polymeric material 36. It should be understood that the mold 54 described herein may be solid, porous, and/or printed with openings to inject the bonding material 28. Thus, as shown, mold 54 defines an inner wall limit 56 and an outer wall limit 58 of tower structure 12. Additionally, the center frame structure 38 may be mounted between the molds 54. Thus, after at least a portion of mold 54 is printed and at least partially cured, printer heads 48, 49 and/or nozzles 52 of additive printing device 34 are configured to dispense bonding material 28 into mold 54 within inner wall limit 56 and outer wall limit 58. In such embodiments, as little of the polymer material 36 as a single layer may be printed and then filled with the adhesive material 28. In an exemplary embodiment, the polymeric material 36 cures more quickly than the bonding material 28; thus, the bonding material 28 may be printed/dispensed immediately after the small amount of polymeric material 36 is applied. In such embodiments, residual heat from the cooled polymeric material 36 (e.g., in the case of a thermoplastic) may also assist in the curing process of the bonding material 28. In other words, the bonding material 28 may be printed after the polymeric material 36 or simultaneously with the polymeric material 36.

In particular embodiments, additive printing device 34 may also be configured to print or place metallic material 50 into bonding material 28 and/or polymeric material 36 to form one or more reinforcing elements 30 (such as any of those described herein) therein. For example, in such embodiments, the printer heads 48, 49 described herein may print a liquid metal material 50, such as steel, titanium, or the like, as is generally understood in the art. Alternatively, the printer heads 48, 49 may be configured as a robotic pick and place type device that can place additive (e.g., such as rebar or composite rebar over several meters in length or coiled steel cable over hundreds of feet in length) into the bonding material 28 and/or the polymeric material 36. In still further embodiments, one or more reinforcing elements 30 may be manually placed in the bonding material 28 before, during, and after printing, but before curing.

Still referring to FIG. 3, the platform 40 of the central frame structure 38 may be movable in a vertical direction to move the central frame structure 38 (and thus the plurality of robotic arms 46) along the central longitudinal axis 44 of the tower structure 12 during dispensing of the bonding material 28. Thus, additive printing device 34 may be linearly translated in a vertical direction for building tower structure 12. More particularly, as shown, additive printing device 34 may include a movement mechanism 60 and/or a climbing mechanism. For example, in one embodiment, moving mechanism 60 may include one or more motorized wheels 62 and at least one linkage 64 to allow for changes in the diameter of tower structure 12 as additive printing device 34 moves along longitudinal axis 44 to print a plurality of tower sections. It should also be understood that the climbing mechanism may include any suitable climbing device. In yet another embodiment, the height of additive printing device 34 may be determined such that once a first section of tower structure 12 is printed, additive printing device 34 may be moved to a second vertical position to print a second section of tower structure 12. In another embodiment, platform 40 of central frame structure 38 may be fixed and robotic arm 46 may translate along arm 42 using a different motion mechanism.

Referring now to fig. 5 and 6, various diagrams of a system 32 for manufacturing tower structure 12 of wind turbine 10 at a wind turbine site are shown. FIG. 5 illustrates a top view of tower structure 12 formed within mold 54. FIG. 6 shows a cross-sectional view of the tower structure of FIG. 6 along section line 6-6. As shown, additive printing device 34 is also configured to print one or more guide structures 66 into bonding material 28. More particularly, in such embodiments, after the bonding material 28 is cured, one or more portions 68 of the mold 54 may be melted to expose the guide structure 66 to provide a support surface for the platform 40 of the central frame structure 38 such that the central frame structure 38 may be moved to a second vertical position for printing the second section 27 of the tower structure 12.

Referring back to FIG. 3, system 32 for fabricating tower structure 12 of wind turbine 10 may also include separate

fluid transfer systems

70, 72, 73, 75 for polymeric material 36, bonding material 28, metallic material 50, and adhesive material 33 (as well as any other materials used to fabricate tower structure 12), respectively, the connections of which are not shown. However, it should be understood that each of

fluid transfer systems

70, 72, 73, 75 may include at least a pump and a storage tank for the respective liquid material configured to store and transfer the respective liquid medium to additive printing device 34.

Suitable polymeric materials described herein can include, for example, thermoset materials, thermoplastic materials, biodegradable polymers configured to degrade/decompose over time (such as grain-based polymer systems, fungal-based additive materials, or algae-based polymer systems), or combinations thereof. Thus, in one embodiment, the outer polymer mold may be biodegradable over time while the inner polymer mold remains intact. In an alternative embodiment, the outer mold and the inner mold may be constructed of the same material.

In additional embodiments, the adhesive material 33 described herein may be provided between one or more of: the bonding material 28 to the base, the bonding material 28 to the polymeric material 36, the bonding material 28 to the metallic material 50, or multiple layers of the bonding material 28, the polymeric material 36, and/or the metallic material 50. Thus, the adhesive material 33 may also supplement the interlayer bonding between the materials.

The binder material 33 described herein may include, for example, a bonding material, such as a mortar, a polymeric material, and/or a mixture of a bonding material and a polymeric material. Adhesive formulations that include a bonding material are referred to herein as "bonding mortars". The bonding mortar may include any bonding material, which may be combined with fine aggregate. Cementitious mortars made using a portland binder and fine aggregate are sometimes referred to as "portland binder mortars" or "OPCs". An adhesive formulation comprising a mixture of a binding material and a polymeric material is referred to herein as a "polymeric mortar". Any binding material may be included in the mixture with the polymeric material and optionally the fine aggregate. Adhesive formulations that include a polymeric material are referred to herein as "polymeric adhesives.

Exemplary polymeric materials that may be used in the adhesive formulation may include any thermoplastic or thermoset polymeric material, such as acrylics, polyepoxides, vinyl polymers (e.g., polyvinyl acetate (PVA), Ethylene Vinyl Acetate (EVA)), styrenes (e.g., styrene butadiene), and copolymers or terpolymers thereof. The properties of exemplary polymeric materials are described in ASTM C1059/C1059M-13, Standard Specifications for Latex Agents for Bonding Fresh To Hardened Concrete (Standard Specifications for adhesive emulsions used To bond New To Hardened Concrete).

Referring now to FIG. 7, a partial detail view of another embodiment of a system 32 for fabricating tower structure 12 of wind turbine 10 is illustrated. As shown, when the bonding material 28 is dispensed between the inner wall limit 56 and the outer wall limit 58, one of the reinforcement elements 30 is shown between the inner wall limit 56 and the outer wall limit 58. In addition, as shown, the reinforcing element 30 is shown as being hollow on the inside. More particularly, the reinforcing element 30 (typically assumed to be a tubular structure) may also have an opening 74 circumferentially positioned at a predetermined height on its surface. In such embodiments, bonding material 28 may be transported through member 30 and pumped through holes 74 of reinforcing member 30 to fill the gap between mold structures 56, 58 (rather than using printer heads 48, 49 and/or injector 52). The various pumps of the

fluid delivery systems

70, 72 described herein may also be configured to vary the pumping pressure to achieve dispensing at a desired height.

Referring specifically to FIG. 8, a flow diagram of an embodiment of a method 100 for fabricating a tower structure of a wind turbine at a wind turbine site. In general, method 100 will be described herein with reference to wind turbine 10, tower structure 12, and system 32 shown in FIGS. 1-6. However, it should be appreciated that the disclosed method 100 may be practiced with tower structures having any other suitable configuration. Additionally, although fig. 8 depicts steps performed in a particular order for purposes of illustration and discussion, the methods discussed herein are not limited to any particular order or arrangement. Using the disclosure provided herein, those skilled in the art will appreciate that various steps of the methods disclosed herein may be omitted, rearranged, combined, and/or adapted in various ways without departing from the scope of the present disclosure.

As shown at (102), method 100 may include printing at least a portion of mold 54 of tower structure 12 of wind turbine 10 of polymeric material 36 on base 15 of tower structure 12 via first printer head 48 of additive printing device 34. For example, in one embodiment, the first printer head 48 of the additive printing device 34 may be configured to dispense the polymeric material 36 to build the mold 54 layer-by-layer on the base 15 (or any other suitable in-situ location) of the wind turbine 10. In certain embodiments, the polymeric material 36 may be printed using an extrusion system that feeds the pellets. Thus, as mentioned, mold 54 defines an inner wall limit 56 and an outer wall limit 58 of tower structure 12.

After the portions of mold 54 are cured, as shown at (104), method 100 may include providing bonding material 28 between inner wall limit 56 and outer wall limit 58 of mold 54 via second printer head 49 of additive printing device 34 while continuously building one or more additional portions of mold 54 with polymeric material 36. As shown at (106), as additional portions of mold 54 continue to cure, method 100 includes continuing to fill additional portions of mold 54 with bonding material 28 until tower structure 12 is established. In such embodiments, residual heat from the recently printed polymeric material 36 may help to cure the bonding material 28 more quickly.

In an alternative embodiment, the injector 52 of the additive printing device 34 may simply inject or fill the mold 36 with the bonding material 28, rather than printing the bonding material 28. In one embodiment, as shown, additive printing device 34 may fill mold 54 from the top. Alternatively, after the mold is formed, one or more holes may be drilled into the sides thereof, and the bonding material 28 may be pumped into the holes at various heights, either constantly or at frequent intervals, to prevent excessive head pressure from building up. Additionally, as shown at (106), method 100 may include allowing bonding material 28 to cure within mold 54 to form tower structure 12.

Referring now to fig. 9, a block diagram of one embodiment of a controller 76 of an additive printing device 34 is shown. As shown, the controller 76 may include one or more processors 78 and associated memory devices 80 configured to perform various computer-implemented functions (e.g., performing methods, steps, calculations, etc., and storing related data as disclosed herein). Additionally, controller 76 may also include a communication module 82 to facilitate communication between controller 76 and various components of additive printing device 34. In addition, the communication module 82 may include a sensor interface 84 (e.g., one or more analog-to-digital converters) to allow signals transmitted from one or more sensors (not shown) to be converted into signals that can be understood and processed by the processor 78. It should be appreciated that the sensors may be communicatively coupled to the communication module 82 using any suitable means.

As used herein, the term "processor" refers not only to integrated circuits referred to in the art as being included in a computer, but also to controllers, microcontrollers, microcomputers, Programmable Logic Controllers (PLCs), application specific integrated circuits, and other programmable circuits. The processor 78 is also configured to compute advanced control algorithms and communicate in various Ethernet or serial-based protocols (Modbus, OPC, CAN, etc.). Additionally, memory device 80 may generally include memory elements including, but not limited to, computer-readable media (e.g., Random Access Memory (RAM), computer-readable non-volatile media (e.g., flash memory), a floppy disk, a compact disc-read only memory (CD-ROM), a magneto-optical disk (MOD), a Digital Versatile Disc (DVD), and/or other suitable memory elements). Such memory devices 80 may generally be configured to store suitable computer-readable instructions that, when executed by the processor 78, cause the controller 76 to be configured to perform various functions as described herein.

This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

Claims

1. A method for manufacturing a tower structure for a wind turbine, the method comprising:

printing, via a first printer head of an additive printing device, at least a portion of one or more molds of a tower structure of the wind turbine of polymeric material on a base of the tower structure, the one or more molds defining an inner wall limit and an outer wall limit of the tower structure;

after the portion of the one or more molds have cured, providing a bonding material between an inner wall boundary and an outer wall boundary of the tower structure via a second printer head of the additive printing device while continuously establishing additional portions of the one or more molds with the polymeric material;

continuously filling additional portions of the one or more molds with the bonding material as the additional portions of the one or more molds continue to cure until the tower structure is established; and

allowing the bonding material to cure within the one or more molds to form the tower structure.

2. The method of claim 1, wherein providing the bonding material between the inner wall boundary and the outer wall boundary via the additive printing device further comprises at least one of: additive printing the bonding material between the inner and outer wall limits via the additive printing device, or dispensing the bonding material between the inner and outer wall limits via at least one nozzle of the additive printing device.

3. The method of any preceding claim, wherein the additive printing device comprises a plurality of robotic arms, each of the robotic arms comprising the first and second printer heads for dispensing the polymer material and the adhesive material, respectively.

4. The method of claim 3, further comprising mounting a center frame structure of the additive printing apparatus between the one or more molds, the center frame structure having a platform and an arm member extending substantially perpendicularly from the platform, the plurality of robotic arms being secured to the arm member, the arm member being substantially parallel to a central longitudinal axis of the tower structure.

5. The method of claim 4, comprising translating the platform in a vertical direction to move the central frame structure and the plurality of robotic arms along a central longitudinal axis of the tower structure during printing of the bonding material.

6. The method of claim 5, wherein translating the platform in the vertical direction further comprises providing a movement mechanism configured to move the central frame structure within the tower structure and allow for a change in diameter of the tower structure as the additive printing device moves along the central longitudinal axis to print a plurality of tower sections.

7. The method of claim 4, comprising rotating one or more of the plurality of robotic arms about the central frame structure.

8. A method according to any preceding claim, wherein the height of the additive printing device is determined such that once a first section of the tower structure is printed, the additive printing device is movable to a second vertical position to print a second section of the tower structure.

9. The method of claim 8, comprising printing, via the additive printing device, one or more guide structures for the plurality of robotic arms into at least one of the bonding material or the polymer material.

10. The method of any one of the preceding claims, comprising dispensing, via the additive printing device, additive material into at least one of the bonding material or the polymer material to form one or more reinforcing elements, the additive material comprising at least one of a metallic material, a composite material, or a non-metallic material.

11. The method of claim 10, comprising providing an adhesive material between at least one of: the bonding material and the base, the bonding material and the polymer material, the bonding material and the metal material, or multiple layers of the bonding material, the polymer material, and/or the metal material.

12. The method of any one of the preceding claims, comprising placing one or more reinforcing elements in at least one of the bonding material or the polymeric material before, during or after printing and before curing.

13. A method for manufacturing a bonded structure, the method comprising:

printing, via a first printer head of an additive printing device, at least a portion of one or more molds of the structure of polymeric material on a base of the structure, the one or more molds defining an inner wall limit and an outer wall limit of the structure;

after the portion of the one or more molds have cured, providing a bonding material between an inner wall boundary and an outer wall boundary of the structure via a second printer head of the additive printing device while continuously establishing additional portions of the one or more molds with the polymeric material;

continuously filling additional portions of the one or more molds with the bonding material as the additional portions of the one or more molds continue to cure until the structure is established; and

allowing the bonding material to cure within the one or more molds to form the structure.

14. A system for manufacturing a tower structure for a wind turbine, the system comprising:

an additive printing device, the additive printing device comprising:

a center frame structure including a platform and arm members extending substantially perpendicularly from the platform, the arm members being substantially parallel to a central longitudinal axis of the tower structure; and

a plurality of robotic arms secured to an arm component of the central frame structure, each of the robotic arms including a printer head for additive printing one or more materials including at least one of a polymeric material, an adhesive material, a metallic material, or a composite material;

at least one nozzle configured to dispense the bonding material; and

one or more molds that are additive printed via an additive printing device of the polymeric material, the one or more molds defining an inner wall limit and an outer wall limit of the tower structure,

wherein at least one of a nozzle or a printer head of the additive printing device is configured to distribute the bonding material between an inner wall limit and an outer wall limit of the tower structure.

15. The system of claim 14, wherein the platform is movable in a vertical direction to move the central frame structure and the plurality of robotic arms along a central longitudinal axis of the tower structure during dispensing of the bonding material.

16. The system of claim 15, wherein the additive printing device further comprises a movement mechanism configured to move the central frame structure within the tower structure and allow for a change in a diameter of the tower structure as the additive printing device moves along the central longitudinal axis to print a plurality of tower sections.

17. The system of claims 14-16, wherein the system comprises one or more reinforcing elements for reinforcing the bonding material.

18. The system of claims 14-17, wherein the polymeric material comprises a biodegradable polymer configured to degrade/decompose over time.

19. The system of claims 14-18, wherein the plurality of robotic arms are mounted for rotation about an arm member of the central frame structure during printing of the one or more materials.

20. The system of claims 14-19, comprising a separate fluid delivery system for each of the one or more materials.